1. Technical Field
The disclosure relates to an inkjet printer configured to perform an efficient purge operation using a predetermined ink with a simple device configuration.
2. Related Art
An inkjet printer is capable of printing images, characters and the like by ejecting ink onto print paper from nozzles in an inkjet head based on print data. Also, the inkjet printer uses multicolor inks to perform color printing of print data on print paper.
The inks used in such an inkjet printer have temperature characteristics such that the viscosity changes with temperature conditions, i.e., the viscosity is high at low temperature and is low at high temperature. Particularly, when the ink viscosity is high, a variation may occur in droplet size or ejection speed of ink droplets, leading to a situation where a high-definition printed matter cannot be obtained.
In this regard, an ink circulation type inkjet printer has been generally well-known, which warms ink with warm water or the like while circulating the ink.
Japanese Patent Application Publication No. 2009-297961 proposes a technique related to an image recording device in which an ink circulation path is formed by an inkjet head configured to eject ink from nozzles, a first tank configured to store ink to be fed to the inkjet head and disposed at a position higher than that of the inkjet head in a vertical direction, a second tank configured to store ink that remains unejected from the inkjet head, and a pump configured to circulate the ink among the first tank, the inkjet head and the second tank. In the image recording device, a pressure adjuster to adjust the pressure in the ink circulation path is provided communicating with the second tank, and the pressure adjuster sets the pressure in the second tank to a negative pressure, thereby circulating the ink.